Static balancing of highly reconfigurable articulated wheeled vehicles for power consumption reduction of actuators

Abstract

This paper presents the static balancing of a highly reconfigurable articulated wheeled vehicles with multiple leg-wheel subsystem. Articulated wheeled vehicles are a class of mobile robots, which offer immense possibilities for enhanced locomotion-performance of autonomous mobile vehicles by virtue of the enormous reconfigurability within their articulated structure. However, changing the vehicle platform elevation could require considerable actuator power because of the payload. Hence, the main focus of this paper is to carefully evaluate various means for reducing or eliminating these static forces, principally due to the mass- and inertia-distribution within the system. It is noteworthy that although known apriori, such static forces often are significantly dependent upon the articulated-wheeled vehicle configuration. Hence, realising the static balancing for all possible configurations of vehicle imposes special set of conditions on the geometric, mass and inertial parameters. In this paper, elastic elements such as springs are used in conjunction with reconfigurable four-bar mechanism to achieve the static balancing. The essential principle is to realise that the total potential energy including the elastic potential energy stored in springs and gravitational potential energy becomes constant. Finally, we show that elimination of static torques due to gravity reduces the torque requirements and provides much more efficient design with significant reduction of the actuator sizes.